@huiz,
I bought that book as a kindle for someone I'm helping to learn c# for Autocad.
He is having no trouble with it , and seems to be progressing quite well so far.
I think you've done a good job of the book . . . well done !
A few of the snapshots are a little dated, but that was easily explained, and resolved.
If I notice any issues I'll let you know.
Regards,